"In many European countries, parents are wary of giving a bilingual education to their kids and try to speak only one language," said study author Jacques Mehler of the Language, Cognition, and Development Lab at the International School for Advanced Studies in Trieste, Italy.

"They are afraid [their children] might suffer when they get to school and so on," Mehler said. "Because of our results, I doubt that very much."

The study involved 40 infants. Half of the participants heard Italian and another language (Slovenian, Spanish, English, Arabic, or Danish) at home. The other half were from Italian-language-only households.

The babies' ability to process language was tested using cartoon critters on a computer screen. Two different types of three-syllable, wordlike sounds were played a split second before one of the characters would appear in one of two areas on the screen.

The experiment was designed to test the babies' ability to anticipate where the creature would appear based on the sound cues.

Unlike the monolingual group, the bilingual group was able to successfully learn a new sound type and use it to predict where each character would pop up.

The bilingual babies' skill applies to more than just switching between languages. Mehler likened this apparently enhanced cognitive ability to a brain selecting "the right tool for the right operation"—also called executive function.

In this basic process, the brain, ever flexible, nimbly switches from one learned response to another as situations change.

Monolingual babies hone this ability later in their young lives, Mehler suggests.

While the babies in the test were still too young to talk, bilingual adults use a similar mental ability when switching between languages, the scientist noted.

Not Necessarily Smarter

The study builds on previous research by Mehler and colleagues that indicates that babies are able to distinguish between the sounds of different languages from a very early age.

But that isn't to say that single-language children don't later catch up with their multilingual contemporaries, Mehler added.

"I would be very conservative about the conclusion that bilinguals are smarter than monolinguals," he said.

Findings to be reported in tomorrow's issue of the journal Proceedings of the National Academy of Sciences.